Secrets stored in the secrets manager can be accessed using the `SECRETS` context: ```${{ SECRETS.<name>.<key> }}```.

For example:

```php
${{ SECRETS.virustotal.VIRUSTOTAL_API_KEY }}
```

Tracecat will automatically replace the expression with the secret value at runtime.
Retrieved secrets are removed from memory, i.e. garbage collected, after the action is executed.
